Electrically actuated tool



Sept. 13, 1938. I YOUNG 2,129,899

ELECTRICALLY ACTUATED TOOL Filed June '7, 1935 2 6 t 3 22 9 r" 33 /0 23 20 72 7/ ii: 7, L i i '1 5 J i T f 1 J I f; Z6 27 a W jg; l. l; I L L M H 29 34 30 1% A5 /3 726 2/ 70 Jamil 500g Patented .Sept. 13, 1938 PATENT OFFICE ELECTRICALLY ACTUATED TOOL John Young, Toledo, Ohio Application June 7, 1935, Serial No. 25,481

13 Claims. (01. 115-265) This invention relates to electrically actuated tools and more particularly to a method and means for performing work upon metals and alloys by the use of electric currents.

The invention comprehends means using any suitable source of electric energy, either alternating or direct current, for marking metals and alloys or causing etching, engraving or other operation thereon by utilizing a combined electrical and mechanical means, the arrangement in itself serving to rapidly interrupt the'electrical circuit. 9

This invention has for one of its objects an improved marking or engraving device which has an electrode rapidly reciprocated by the electric current flow therethrough.

Another object of the invention is to provide a compact self-contained electro-magnet having a marking or engraving element, the winding of the magnet serving as resilient or mechanical means to reciprocate the engraving element when the current is interrupted.

A further object of the invention is the provision of a device of this character which perates on comparatively low voltages and wherein one of the sections of the core is readily adjustable for purposes of varying the intensity or amplitude of the vibrating electrode carrying the engraving element.

Still a further object is the provision of a ventilated housing for an engraving arrangement of this character whereby heat generated at the point of arc and the current flow is readily dissipated, and the invention further embraces a friction connecting means whereby the engraving device may be readily disconnected from the current supply and placed in a liquid cooling medium.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of-a form of the invention, which may be preferred, in which:

Figure 1 is a longitudinal sectional view showing the arrangement of parts of the engraving device of my invention;

Figure 2 is aside elevational view of the arrangement illustrated in Figure 1; Figure 8 is a transverse sectional view taken substantially on the line H of Figure 1;

Figure 4 is a transverse sectionakview taken substantially on the line 4-4 of Figure 1;

Figure 5 shows a form of frictional connection for readily attaching the engraving device to a current supply wire;

Figure 6 is a general arrangement showing the method of using the engraving device of my invention utilizing an especially constructed transformer in conjunction with a source of alternating current;

Figure 7 is a view showing a further method of utilizing the engraving device wherein direct current is used coupled with an adjustable resistance bridge as a current controlling means;

Figure 8 illustrates an arrangement wherein the casing of the tool may be fabricated of metal and insulatingly supported from surrounding structures.

While I have illustrated the arrangement of my invention as of a particular character and size for use in carrying out usual engraving operations, it is to be understood that I contemplate the arrangement of my invention for various sizes of engraving devices usable for comparatively heavy work, as for example, in marking castings or in making comparatively deep serrations in metals or alloys of all kinds.

, Referring to the drawing in detail, numeral l0 designates a sleeve member fabricated of phenol condensation product or other suitable insulating material which forms a housing for the interior mechanism as well as an adequate means of holding the engraving device during engraving operations. Snugly fitted within each end of the sleeve ID are the bushings l2 and I3 which may be of suitable material, as for example, bronze or a bearing alloy. The bushing I3 is arranged to snugly receive a cylindrical member l5 having a projecting reduced portion is centrally bored and threaded as illustrated in Figure 1. This threaded bore is adapted to receive a core member of magnetizable material such as soft iron or the like having a smooth cylindrical portion l9 and a threaded portion which is received in the bore of member IS, a transverse kerf 2i being arranged in the outer end of core member l8 so as to accommodate a screw driver or tool for adjusting the core member with respect to cylindrical member IS. The sleeve or housing [0 is fixedly secured to member ii by means of a screw 23- passing through an opening in the sleeve lllthrough bushing l3 and into a threaded bore in the member 15 as particularly shown in Figure 2.

Slidably received in the bushing ii in the opposite end of the sleeve in is a plunger 24 of brass or suitable current; conducting material which is provided with a longitudinal central bore to receive an engraving element 26 or other tool actuated by reciprocatory action with respect to the work.

I have found that there are numerous materials and alloys forming suitable engraving tools but that tungsten or an alloy of copper and tungsten have been found to be entirely satisfactory. The engraving element or tool is held in place in plunger 24 by means of a set screw 21. The plunger 24 is preferably polygonal in cross section as indicated in Figure 3 and reciprocates in the cylindrical interior of bushing I2. I have found that a non-circular configuration for the plunger provides spaces between the plunger and the interior walls of the bushing so as to decrease the friction between these parts and provide spaces for the passage of air or other medium for the purposes of cooling the electrode.

The inner end of plunger 24 is provided with a portion 29 which may be a separate member or may be integral with the plunger 24. This member 29 is centrally bored to accommodate another core member 39 of magnetizable material such as soft iron which forms another part or section of the core structure.

In the embodiment illustrated, the members l5 and 29 are joined together by means of a helix or spiral element 32 which is of a current conducting material. The extremities of the helix are brazed or welded as at 33 and 34 to the members l6 and 29 so as to virtually form an integral structure. I have shown the helical portion 32 as constructed of material of rectangular cross section, but it is to be understood that any current conducting material of suitable cross section, as for example, a round section may be used without departing from the scope of the invention.

As will be hereinafter further explained, the core sections l6 and 36 are slightly separated to form a gap 22 as illustrated in Figure 1 and this gap may be varied by rotating core section II! through the use of a suitable tool insertedin the kerf 2|. The purpose of this separation is to permit a reciprocating movement of core section 36, member 29, plunger 24 and engraving tool 26 and to change the magnetic gap. The sleeve I I is perforated with openings ll so as to provide ventilating means to facilitate cooling of the arrangement as the passage of current through the helix or coil 32 and the voltaic are occurring at the point of application of tool 26 to the work plate 66, the tool and its holder conducts heat generated by the arc into sleeve l9 and is dissipated through openings ii in the sleeve.

In the embodiment illustrated the lead wire to the engraving device is connected to a bushing III by inserting the end of the lead wire in bore H thereof, the same being-held in place by means of a set screw I2. The bushing 10 is pressed into a sleeve I4 of Bakelite or other suitable insulating material. The other end of the bushing I6 is slotted longitudinally and bored substantially the length of the slots as indicated at I6 to accommodate the projecting portion ii of member IS. The bore 16 is slightly smaller than the exterior diameter of portion l6 so that the side walls of the bushing adjacent the slotted portion are slightly expanded when the bushing is slipped over the projection ll .so that the parts will be held in close frictional contact to establish good electrical contact therebetween.

Figure 6 illustrates one arrangement in the utilization of the engraving tool. A source of alternating current supply 40 supplies electrical energy which passes through the primary coil 4| of a transformer, the latter being provided with spaced taps 42 cooperating with a switch arm 43 for varying the effective number of turns in the primary of the transformer thus varying voltage obtainable from the secondary. The secondary of the transformer 44 is provided with taps 45, 46 and 41 providing the means for connecting the secondary of the transformer to the engraving tool and the element to be engraved respectively. In the arrangement illustrated tap 45 is connected by means of lead 46 to a clip 49 adapted to be secured to a plate 59 or other element to be engraved, the tap 46 being connected by means of a lead 52 to the removable connection 10 of the engraving device.

If the leadwire 52 is connected to the tap 41 a different voltage is supplied to the engraving took-that is, the voltage across the complete secondary of the transformer. A further voltage variation may be attained by connecting lead 44 to the tap 46. In addition to these taps for attaining diiferences in voltage, a further voltage may be obtained by connecting the switch arm 43 selectively with one of the taps of the series of taps 42. In this manner a considerable adjustment of voltage may be obtained for various classes of engraving.

In the operation of the arrangement of my invention, the engraving tool is utilized in the same manner as when writing with a pencil, and assuming that current is supplied to the primary of the transformer and the element 26 of the engraving tool touches the plate 56, the circuit is completed and a current flows through the secondary of the transformer the coil 32 of the arrangement, thus in effect producing a solenoid, magnetizing the iron core sections I 8 and 36 and due to the gap 22 and the resiliency of the coil 32 the engraving point 26 will immediately be retracted from engagement with the work or plate 50. At the instant of this retraction, current flow between the engraving tool and the plate is broken causing a voltaic are leaving a serration in the work and the retractile stress in the coil 32 drives the engraving point or tool 26 again into the plate 56 at which time the circuit is again completed and current flows through coil 32 and the retracting action on tool 26 is repeated. At each expansive movement of coil 32, the engraving point 26 is driven into the plate at which time the circuit is again completed and current flows through coil 32 and the retracting action on tool 26 is repeated. At each expansive movement of coil 32, the engraving point 26 is driven into the plate aided by the inertia of the parts 24 and 29 as well as core section 36. This reciprocatory action of the engraving point 26 is very rapid and I have found from experience as many as 180 impulses a second are imparted to the engraving point. Thus, through the medium of such a high periodicity of vibration and the inherent characteristics of the arc to displace or deform metal of the work adjacent the point of application of the tool the engraving or other useful work may be accomplished very rapidlyin fact, as fast as writing with an ordinary pencil, the engraving line or serration being practically continuous.

In the embodiment of the transformer illustrated in Figure 6, I have shown the lead wires 46 and 52 as connected across the taps 45 and 46 giving apredetermined voltage which may be current.

varied by adjusting the switch arm 43 to a dinerent tap of the series of taps 42. In the event higher voltage is desired, the tap 41 may be connected to the lead 52 as illustrated in dotted lines at 52', thus utilizing the entire secondary winding of the transformer. The voltage between taps and 41 may further be varied by adjusting the switch 43 in the primary circuit as hereinabove described.

I have found that the depth of engraving and the hardness of the material operated upon necessitates a variation in the voltage and current delivered through the coil 32 to the engraving tool. In this connection, I have found that for ordinary engraving uses, voltages from to 6 volts are satisfactory, although any desired voltage may be obtained by using a transformer having different ratios of windings as well as utilizing primary voltage of diiferent intensity. The use of current of low voltage and comparatively low amperage in circuit with the engraving tool are found to be quite satisfactory in that the engraving is more or less accomplished by the impact of the tool 26 driven into the plate rather than through the excessive currentas has been utilized in prior engraving devices. Thus, I have obtained satisfactory engraving without danger of burning the metal or work operated upon by utilizing comparatively low voltage and current in the circuit of the engraving tool.

Figure '1 illustrates an arrangement of utilizing the engraving tool of my invention with direct current, as for example, dry cell batteries or storage accumulators. One side of the battery is connected to the engraving tool, the other side being connected by means of a lead 62 to the adjustable arm 63 of a resistance bridge R, the extremities of the bridge being connected as at 64 and 65 to the plate 50" to be engraved. The solenoid arrangement in the engraving tool of my invention operates equally well on direct current and the voltage impressed upon the work plate 50" may be varied by adjusting the position of the arm 63 to vary the effective resistance R, thus efiecting a change in the voltage and the I have found that satisfactory engraving may be accomplished through the use of direct current as above described and as the current utilized is quite high, it has been found desirable in utilizing dry cells to connect a plurality of sets of dry cells in parallel so as to prolong the life of the current source without increasing the voltage.

Under certain conditions of continued use, the device will become heated because of the heat discharged by reason of the current fiow and areing, and'in such event it is only necessary to withdraw the connector sleeve 10 from engagement with the projection i6 and the device placed in water or other suitable cooling liquid. The liquid will circulate through the ventilating openings ii and through the interstices between plunger 24 and sleeve I? so that the heat will be quickly dissipated. In a very short time the engraving device may be withdrawn from the cooling medium andthe connection reestablished through sleeve 10. The cooling medium will drain out through the openings ii and the interstices above mentioned so that it requires but a hort period of time in order to completely cool hestructure and resume engraving or other operations.

The adjustability of the gap 22 between the core sections i8 and 30 has been found to be quite desirable as in adjusting this gap there is the magnetic pul upon core II and the engraying tool 26, thus permitting an extremely fine adjustment of the magnetic forces which permits the utilization of comparatively low voltage and current which reduces arcing and tendency to burn the work.

In the arrangement shown in Figure 8, the casing III of the tool may be fabricated of metal or alloy and in order to direct .current flow through the coil 32' the bushing I?!" may be fabricated of insulating material, as for example, Bakelite, fibre, or the like. By this arrangement, the current flow will be directed through the coil 32.

It is apparent that, within the scope of the invention, modifications and different arrangements may be made other than is herein disclosed, and the present disclosure is illustrative merely, theinvention comprehending all variations thereof.

What I claim is:

1. In a device of the class described, including a casing; a current conducting coil within said casing including a plurality of spaced convolutions forming a resilient structure one end of which is relatively fixed with respect to the casing; a relatively fixed magnetizable member in said casing; a second magnetizable member positioned adjacent the free end of said resilient current conducting member; and a tool carried at the free end of the resilient structure.

2. In a device of the class described, including a casing; a current conducting coil within said casing including a plurality of spaced convolu-' tions forming a resilient structure; means to fixedly secure one end of said structure to said easing; a plunger reciprocally mounted in said casing; a magnetizable member located within said convolutions and connected to said plunger; a portion of said plunger being fixed to the free end of said resilient structure; the convolutions being arranged whereby when current flows therethroughthe magnetizable member is actuated to compress the resilient structure and when the current is interrupted the resilient structure returns the magnetizable member to its normal position.

3. A device of the character disclosed including a casing; a reciprocable element positioned within the casing and having a projecting core of magnetizable material; a coil spring surrounding the projecting portion and connected to the reciprocable element, said spring adapted to conduct current to said reciprocable element and simultaneously magnetize said projecting core; and a tool carried by said reciprocable element.

4. A device of the character disclosed, in combination, a housing of insulating material; a reciprocable element partially contained within said housing, said reciprocable element having a projecting section of magnetizable material; a sleeve fixed within said housing and having a threaded bore; a second section of magnetizable material threaded into said sleeve; a current conducting coil connecting said reciprocable element with said stationary sleeve, said second section of magnetizable material being adjustable longitudinally to vary the gap between said sections of magnetizable material.

5. A device of the character disclosed, in combination, a cylindrical housing of insulating material; a reciprocable element partially contained within said housing, said reciprocable element having a projecting section of magnetizable material; a'second section of magnetizable material supported on said housing; a current conducting coil connected to said reciprocable element, said second section of magnetizable material being adjustable to vary the gap between said sections of magnetizable material.

6. A device of the character disclosed, in combination, a housing of insulating material having ventilating perforations in the walls thereof; a reciprocable element extending into said housing, said reciprocable member having a portion 01' magnetizable material; a current conducting coil surrounding said portion of magnetizable material and connected to said reciprocable element; said coil having spaced convolutions forming a resilient structure and a tool carried by said reciprocable member.

7. A device oi the character disclosecf'in combination, a housing of insulating material; a reciprocable element partially contained within said housing, said reciprocable member having a projecting portion of magnetizable material; a sleeve positioned within said housing and having a threaded bore; a shaft of magnetizable material threaded into said sleeve; a current conducting coil spring connecting said reciprocable element with said stationary sleeve, said shaft of magnetizable material being adjustable longitudinally to vary the gap between said shaft and the projecting portion of magnetizable material carried by said reciprocable member; and means for connecting a current supply lead to the sleeve.

8. A device or the character disclosed, in combination, a housing of insulating material having ventilating openings in the wall thereof; a reciprocable element partially contained within said housing, said reciprocable member having a projecting portion of magnetizable material; a sleeve secured within said housing and having a threaded bore; a. shaft of magnetizable material threaded into said sleeve; 9. current conducting coil spring connecting said reciprocable element with said sleeve, said shaft of magnetizable material being adjustable longitudinally to vary the gap between said shaft and the projecting portion of magnetizable material carried by said reciprocable member; means for irictionally connecting a current supply lead to the stationary sleeve including a split bushing; a sleeve of insulating material surrounding said bushing; and means for securing a current supply wire to said bushing.

9. A device oi the character disclosecLin combination: a housing i'ormed of insulating mate rial; a member secured to said housing having a projecting portion: an iron core adjustably carried by said member: a reciprocable element in said housing having a projecting iron core; a current conducting coil connecting said member and reciprocable element; means for connecting a lead wire to the projecting portion of said first mentioned member including a slotted sleeve adapted to be frictionally retained on said projecting portion; and a sleeve of insulating mate'- rial secured to said slotted sleeve.

10. A device of the character disclosed, in combination: a housing formed of insulating material; a member fixed in said housing and having a projecting portion; a reciprocable member in said housing having an iron core; a current conducting coil connected to said reciprocable member; means for connecting a lead wire to said fixed member including a slotted sleeve adapted to be frictionally retained on said projecting portion; and a sleeve of insulating material secured to said slotted sleeve.

11. A device of the character disclosed, in combination, a housing of insulating material having ventilating openings in the wall thereof; a reciprocable element partially contained within said housing, said reciprocable element having a projecting portion of magnetizable material; a sleeve fixed within said housing and having a threaded bore; a shaft of magnetizable material threaded into said sleeve; a current conducting coil spring connecting said reciprocable element with said relatively stationary sleeve, said shaft of magnetizable material being adjustable longitudinally to vary the gap between said shaft and the projecting portion of magnetizable material carried by saidreclprocable member; means for connecting a current supply lead to the stationary sleeve including a split bushing; a member 01' insulating material surrounding said bushing; and means for securing a current supply wire to said bushing. i

12. In a device of the class described including a casing; a current conducting coil within said casing including a plurality of spaced convolutions forming a resilient structure; a plurality of magnetizable members within said casing, one of said members being relatively fixed with respect to said casing, the other of said members being relatively movable therein; and a tool con nected to the relatively movable member.

13. A device of the character disclosed including a casing; a reciprocable magnetizable member positioned within the casing; a second magnetizable member spaced from said reciprocable magnetizable member; a current conducting helix within said casing connected to said reciprocable member, said current conducting helix when energized adapted to magnetize said magnetizable members to cause reciprocation of said reciprocable member.

JOHN YOUNG. 

